DIETARY ASTAXANTHIN ON HEPATOPANCREAS LIPID METABOLISM AND OVARIAN DEVELOPMENT OF FEMALE LITOPENAEUS VANNAMEI

This study aimed to investigate the effects of different levels of astaxanthin on the lipid metabolism and ovarian development of famale Litopenaeus vannamei. Four diets with different concentrations of astaxanthin (0, 40, 80 and 120 mg/kg) were formulated to provide equal amounts of nitrogen and energy, and a feeding trial was conducted for 30d. Results showed that the 80 mg/kg group exhibited significantly higher weight gain, gonadosomatic index, and average egg production compared to the control group (P<0.05), however, the 120 mg/kg group had no significantly effect (P>0.05) and exhibited hepatopancreatic atrophy. Supplementing the diet with 80 mg/kg astaxanthin increased the activity of T-AOC and the of content T-SOD, thereby enhancing the antioxidant capacity of female shrimp. Moreover, the addition of 80 mg/kg astaxanthin reduced the content of SFA in the hepatopancreas while increasing the content of MUFA, EPA, and ARA. It also decreased the expression of fas and srebp1, and increased the expression of fabp1 and fatp in the hepatopancreas (P<0.05). Transcriptome analysis of the ovarian tissue revealed that differentially expressed genes were mainly involved in pathways related to “steroid hormone synthesis”“glycerophospholipid metabolism” and “glutathione metabolism”. Moreover, compared to the control group, the 80 mg/kg group exhibited significantly upregulated expression of genes invloved in amino acid metabolism and steroid hormone synthesis, such as gls, pla2, and mfe (P<0.05), while the 120 mg/kg group had significantly downregulated expression (P<0.05). In conclusion, this study demonstrated that adding 80 mg/kg of astaxanthin to the diet of female Litopenaeus vannamei can reduce fatty acid synthesis and deposition, promote fatty acid absorption and transport, and improve ovarian development and related gene expression, thereby enhancing reproductive performance of female shrimp.